Process of hardening steel.



I To all whom' it mayconcerm AR GUSTAV MEISSNER :Aiin ROBERT 'snnnnwrrz, or MAehEBURe,

" aflennii u-m w success or HA esjume' srsrr;

I srs'crr cnrion mg pe t creates Para its. 646,528, dated Apri1-3,190fii Applioatidn filed July 22, 1899.; a1.1;m. .8o7. (r specimens.)

Be it known thatwe; CARL GUSTAV M1 5; NER,irOI1-WOIkS proprietor, and ROBERT 'BEN.-

NEWITZ,engineer, subjectsof the German Emperor, residing at 40 Augustastrasse, Magdetempering of the steel after hardening, as is the case withordinary processes, is not necessary, and, on the other hand, prevents the bursti'ngor fracture of the steel. After the steel is sufficiently heated it is immersed in one bath only for cooling, the said bath being composed of the following constituents,

viz: about three parts, of water and-one part of a mixture comprising about one part, by weight,of zinc-white; one part, by weight, of charcoal-dust; one part, by weight, of leather liquor; one part, by weight, of petroleum. The three parts of water are intimately mixed with the one part of the above mixture. In this manner the steel has imparted to it an exceptional hardness, bursting or fracturing of the steel is practically prevented, and the 1 'cuttingiefficiency of the steel is in nowi:

prejudiced. 7 p v Thereis no necessityto coat-thesteel,

before heating it. 4 v

I The leather liquor herein'above referred to about twenty-four hours, aft-er which the liqwise. The liquor is thenre'ady for use. This liquor may be prepared in anyquantities' and stored in barrels for use.

What we claim as ourinvention, to secure by Letters Patent,is+-'; The process of hardening steel, which conand desire with sists in cooling the heated metal in a bath v 35, any substance, such as whitening or varma if;

is obtained by boiling in ten liters of water, one kilo of tanned leatherarasteiiroin leather which has not been in. previous use orundergone any changes after tanning until the leather has softened and is leached out, the. leather being-allowed to remain in the liquor; nor is filtered off, as in a filteri-press or other- 

